Bernard Heuvelmans was a Belgian-French scientist, explorer, researcher, and writer probably best known, along with Scottish-American biologist Ivan T. Sanderson, as a founding figure in the pseudoscience and subculture of cryptozoology. His 1958 book On the Track of Unknown Animals is often regarded as one of the most influential cryptozoology texts.

Ivan Terence Sanderson was a British biologist and writer born in Edinburgh, Scotland, who became a naturalized citizen of the United States. Sanderson wrote on nature and travel, and was a frequent guest on television talk shows and variety shows of the 1950s and '60s, displaying and discussing exotic animals.